There is growing evidence that the stress of caring for a relative with Alzheimer's Disease (AD) may have important adverse effects on the caregivers. While limited longitudinal data suggest that caregivers are at high risk for depression, little is known about the salient psychosocial factors that may be influential moderators. Moreover, although some evidence suggests that caregiving responsibilities may be associated with health impairments, possible stress-related changes in caregivers' health have not been studied using objective physiological measures. In order to better understand the longer-term mental and physical health consequences of caregiving for AD victims, we will obtain psychological data, blood samples for immunological and nutritional analyses, and health status information from 210 AD family caregivers at three sample points separated by 10-12 months. The mental and physical health impact of caregiving responsibilities will be evaluated by comparing the results obtained with the caregivers with data collected at the same intervals from 100 category-matched (age, sex, and socioeconomic status) comparison subjects who do not have responsibility for an impaired family member. Analyses of caregiver data will be used to identify the best predictors of psychological and immunological functioning in caregivers. The results of these analyses will provide the basis for constructing causal models to specify key mediators of caregivers' emotional and physical health. A better understanding of these key mediators is essential for both the identification of at-risk caregivers, and for the design of effective intervention programs.